SQL Syntax to SSIS Expression Syntax

Expressions are a very powerful way to build flexibilty into packages, however people (like me) who have come from a SQL database background into developing SSIS packages often struggle to get to grips with the syntax used in SSIS expressions.

Here I have noted some SQL syntax and the SSIS expression equivalent:

SQL	SSIS Expression
AND	&&
OR	||
=	==
<>	!=
ISNULL()	ISNULL()
IS NOT NULL	!ISNULL()
CHARINDEX()	FINDSTRING()*
CONVERT(DateTime, '2007-12-04')	(DT_DATE)”2007-12-04”

*Both functions return the location of the occurence of the character, however CharIndex starts from a specified location, whereas FindString looks for the specified occurrence of the string/character. 

Helpfully, many functions are the same between the two languages, for example GETDATE() and LTRIM() work in exactly the same way in expressions as in SQL.